The present invention relates to garments for wear in hazardous environments and, more particularly, to firefighter garments.
In order to meet applicable standards, a firefighter garment must withstand certain levels of abrasion, heat and moisture. Typically, these requirements have been met by providing a firefighter garment having an outer shell made of a heat and flame resistant aramid fiber such as NOMEX (a trademark of E. I. DuPont de Nemours & Co., Inc.), a moisture barrier positioned within and adjacent to the outer shell and a thermal liner, typically made of a batting of aramid fiber quilted to a woven facecloth of spun yarn fiber and positioned within and adjacent to the moisture barrier. Originally, the moisture barrier was made of a fabric coated with a neoprene rubber compound which made the moisture barrier impermeable to moisture vapor as well as liquid vapor.
However, moisture barriers are now available which comprise a layer of a semi-permeable membrane material such as GORE-TEX (a registered trademark of W. L. Gore & Associates, Inc.) adhesively attached to a substrate of an aramid fiber. Such moisture barriers are impermeable to liquid moisture but allow moisture vapor to pass through.
A disadvantage with such conventional firefighter garment construction is that, when worn, the rigors of firefighting activity results in a build up of excessive levels of moisture vapor from perspiration of the wearer. The flow of such moisture vapor through the semi-permeable moisture barrier membrane is impeded somewhat by the presence of the thermal liner material between the wearer and the moisture barrier. Collection of moisture from the wearer in the thermal liner has been found to reduce the thermal protective qualities of the thermal liner.
Another disadvantage of such conventional firefighter garments is that the necessity of placing the moisture barrier outside the thermal liner, between the thermal liner and outer shell, exposed the moisture barrier to heat penetrating the garment before the heat reached the thermal liner. Consequently, such moisture barriers would be prone to damage and degradation from exposure to heat.
This disadvantage has been overcome by substituting a low or non-absorbent material, such as an apertured, unicellular or closed cell foam laminate for the traditional fabric batting thermal liner. Such closed cell foams, which are heat and flame-resistant, do not themselves absorb outside source moisture from hoses or foul weather, as do conventional woven or fibrous thermal liners, so that they may be placed outside of the moisture barrier, between the moisture barrier and outer shell. This orientation protects the moisture barrier from heat damage, reducing the cost of repairs to the garment, since the moisture barrier is often the most expensive and delicate component in the liner system. It is neither practical nor desirable to place conventional thermal liners outside the moisture barrier since such thermal liners would absorb moisture and add to the weight of the garment. Such non-absorbent thermal liners are disclosed in commonly-owned copending application Ser. No. 119,474, filed Sep. 10, 1993, the disclosure of which is incorporated herein by reference.
A known practice in the industry is the reduction of stress experienced by the wearer of a firefighter garment resulting from the effort required to overcome the frictional engagement of the wearer's clothing with the interior layer of the garment during wearer movement by providing a "slippery" facecloth between the wearer and the thermal barrier of the garment. Such a slippery facecloth also facilitates the donning and doffing of the garment. The facecloth is made of a filament yarn woven or knit into woven or knitted fabric preferably composed of an aramid fiber such as NOMEX. However, such firefighter garments having a filament facecloth still embody the traditional orientation of an outer shell covering a moisture barrier which, in turn covers a thermal liner.
As a result, such firefighter garments include three distinct layers: an outer shell, a moisture barrier consisting of a semi-permeable membrane bonded or laminated to a fabric substrate and a thermal liner positioned within the moisture barrier and quilted to a facecloth. Accordingly, there is a need to provide a firefighter garment having the benefits of a non-moisture absorbent thermal liner with the stress reduction and increased work efficiency of garments with filament layers.